/Engine/Plugins/Runtime/MassGameplay/Source/MassReplication/Public/MassReplicationSubsystem.h
Adds a Client and sets up all the data relevant to the bubble. Where there are multiple viewers for one NetConnection only the parent net connection should be added here
void AddClient ( [FMassViewerHandle](API\Plugins\MassLOD\FMassViewerHandle) ViewerHandle, [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) & InController )